The source audio track is sent (master send disabled) to 6 other tracks, each with a ReaFIR plugin to define the bands. Subs, Lows, Low Mids, High Mids, Highs and Ultra Highs. After that is a simple compressor for each band. You can insert any other plugins you want for each band: Saturation, stereo width etc. You may find this to be a good starting point for mastering.

before spending big bucks on a software package (or worse, pirating it), try Reaper – it’s fully operational straight away and you’re free to demo it for as long as you want, has features enough to rival a lot of commercial packages and only costs $40 if you decide to support it at some point by registering it.